Big-end bearing set 320/09340 JCB Dieselmax +0.50 mm, aftermarket

Big-end bearing set 320/09340, +0.50 mm is an aftermarket part for the JCB Dieselmax 444 engine. The card also lists 320/09207.

Big-end bearings are the thin shells on which the connecting rod runs on the crankpin, carried by a pressurised oil film. The set holds the upper and lower shells for four rods. A worn bearing lowers oil pressure and causes knocking under load and a spun bearing. The size follows the crankpin: standard for a shaft that has not been reground, undersize for a reground one. The shell size is marked on the back of each shell, showing standard or the undersize value.

Specifications

Compatibility

The part is listed for JCB 3CX and 4CX backhoe loaders. An undersize set is chosen after the crankshaft has been reground, to the journal size given by the grinding shop. The catalogue also has the genuine version and aftermarket version of this part. For the rod bolts see the connecting rod bolt 320/03040. Other parts are in JCB Dieselmax engine.

Fitting

The shells go in oiled, with their backs dry and clean. The rod cap must not be turned round: the numbers on cap and rod face the same side. Change the engine oil and filter after assembly and watch the oil pressure on first start.